This extensions has been superseded by the Autolock Extension, which you are encouraged to install, instead. That extension permits locking of page edits, creations, and deletions via regular expression matching on page names, in similar – though, more elegantly customizable – fashion to the Lock Expression On Creation extension, here.

This is small module that takes a list of perl expressions and when a new page is going to be created checks it againstt the name of the new page. If it matches any of the elements of the list and the user is not admin, then the page cannot be created.